CINCINNATI (AP) — Nine Ohio and West Virginia residents who have cancer and other diseases have filed federal lawsuits this month against chemical giant DuPont, alleging the company knowingly contaminated drinking-water supplies with a chemical used by one of its plants.

The lawsuits, filed Oct. 8 and this week, are among about 50 such cases — including one alleging wrongful death — filed against DuPont since April, when a court-appointed science panel found probable links between exposure to perfluorooctanoic acid, also known as C8, and kidney cancer, testicular cancer and thyroid disease, among others.

DuPont, based in Wilmington, Del., uses C8 at its plant near Parkersburg, W.Va., on the Ohio line but plans to stop making and using the chemical by 2015. C8 is a key ingredient in Teflon, the coating used on cookware, clothing and other products.

The recent litigation is the latest in a yearslong battle between DuPont and residents of the Mid-Ohio Valley, in the heart of Appalachia along the Ohio River.

About 80,000 area residents filed a class-action lawsuit against the company in 2001. It resulted in a settlement in which DuPont agreed to pay as much as $343 million for residents’ medical tests, the removal of as much C8 from the area’s water supply as possible and a science panel’s yearslong study into whether C8 causes disease in humans.

“These are folks who’ve been waiting many, many years to be able to pursue these claims,” said Rob Bilott, a Cincinnati attorney who has been working on the case for more than 15 years and represents the Mid-Ohio Valley residents. “Our goal is to be able to get these resolved for them and move forward as quickly as we can.”

In a written statement, DuPont spokesman Dan Turner pointed out the company’s efforts to pay for the medical study of C8 and fund a medical monitoring program for residents exposed to the chemical.

“Lawsuits such as these ignore family history, lifestyle choices and other causes of health issues and disease in specific individuals,” Turner said. “DuPont will vigorously defend against any and all such lawsuits not based upon valid science.”

The roughly 50 recent lawsuits in Ohio and West Virginia, which seek unspecified damages, have been consolidated into one case being presided over by a federal judge in Columbus. The first trial in the matter is set for September 2015.

Many of the lawsuits are more than 50 pages long and accuse the company of negligence, concealment, fraud, deception, battery and the “negligent, intentional and reckless infliction of emotional distress and outrage.”

The lawsuits allege that DuPont’s own research had concluded by at least 1961 that C8 was toxic and it conducted studies in the 1980s showing higher-than-normal birth defects among babies born to its female employees.

DuPont is accused of recklessly, maliciously and knowingly ignoring the risks and releasing C8 into the air and groundwater through its production practices, all while telling members of the public and news media that C8 was safe.

“No reasonable person could be expected to endure the knowledge that an entity has knowingly and intentionally exposed them to years of harmful contact with a dangerous chemical, and has furthermore actively misrepresented and/or concealed such danger from them, while reaping hundreds of millions of dollars in profits as a direct and proximate result,” the lawsuit says.

The lawsuits quote internal notes written by DuPont’s attorneys, obtained during previous litigation, that show their apparent frustration.

“Too bad the business wants to hunker down as though everything will not come out in the litigation,” wrote one attorney who was not named in 2001, according to the lawsuit. “God knows how they could be so clueless. Don’t they read the paper or go to the movies?”

Among the lawsuits is one filed by Virginia Morrison of Parkersburg, W.Va., accusing DuPont of causing the death of her husband in 2008 from injuries related to kidney cancer.

DuPont denies all the allegations in court filings, saying that plaintiffs’ damages, if any, were caused by acts of God or actions of others, “over which DuPont had no control,” and were not reasonably foreseeable by the company.